U.S. Pat. No 4,112,794, owned by the Assignee of this application, discloses therein a tube cutoff device employing a cutoff assembly which is concentric with and rotates around a stationarily supported tube to permit cutting thereof into selected lengths. The rotatable cutoff assembly includes three contact members which are equally angularly spaced around the tube, two of the members being support rollers and the third being a cutter. The cutoff device of this general type is well known and has proven highly desirable for use in cutting tubes into selected lengths. The device disclosed in the above-mentioned patent, however, employs a rotatable cam for effecting relative rotation between the cutoff head and the tube, with the cam being controlled by a phase-change mechanism. While this prior apparatus is extremely desirable for high production rates and for handling different diameter tubes, nevertheless numerous applications require the utilization of a tube cutoff device of a simpler and more compact nature.
U.S. Pat. No. 3,772,945, issued to Varga, also discloses a tube cutoff device employing a rotatable cutter head of the same general type described above. The device of Varga is of a simpler nature, however, in that it is designed for cooperation primarily with a stationarily supported tube, with the cutter head rotating therearound and the cutter being cammed radially inwardly to engage and hence cut the tube. The cutter head of Varga is conventional and operates in a desirable manner. However, the overall device of Varga has exhibited structural and operational characteristics which are believed less than optimum. For example, the Varga device actuates the cutter and rollers by means of an axially slidable cam, which cam is controlled by a rotatable collar having a follower groove therein for confining a cam roller associated with an axially reciprocal slide. This structure, due to the continued high speed rotation between the rotatable collar and the axially shiftable slide, causes excessive wear. This structure is also more subject to binding due to the structural and functional relationships which exist between the cooperating components of the activating linkage.
The present invention thus relates to an improved tube cutoff device which overcomes the above-mentioned disadvantages, and which is believed to provide a more optimum and compact structure for use in cutting a stationary tube into selected lengths, which device is able to accomplish the cutting operation simply and efficiently while permitting accurate yet simple control over the radially movable cutter.
Other objects and purposes of the invention will be apparent to persons familiar with devices of this general type upon reading the following specification and inspecting the accompanying drawings.